Cey, EdwinHall, Glenn2022-01-242022-01-242022-01Hall, G. (2022). Evaluating the effectiveness of bioretention systems for managed aquifer recharge in cold climates (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.http://hdl.handle.net/1880/114326Bioretention systems are a low impact development (LID) technology being utilized to mitigate the flooding and contamination impacts of urbanization on stormwater runoff. These systems are difficult to monitor in cold climates using traditional water-budget techniques when surface temperatures drop below freezing. A bioretention system in the Town of Okotoks, Alberta Canada was investigated to address four objectives. 1) Develop a method to monitor the system year-round. 2) Investigate seasonal changes in the infiltration and recharge characteristics of the system. 3) Determine if there was evidence of nutrient leaching from the system. 4) Develop a technique to estimate recharge from the system. The site was instrumented using a paired monitoring well set-up that allowed for characterization of the local groundwater mound induced by recharging waters. The solution of Hantush was used to calculate the recharge rates required to produce observed groundwater mounding heights and estimate the recharge produced by the bioretention system on a per-event basis. The method overestimated recharge by a factor of three compared to estimates obtained using the water budget technique, but could be corrected by finding an appropriate K value to match the water budget data. The system was estimated to recharge 2500 m3 of stormwater over two years. Winter snow-melt events produced recharge volumes comparable to those induced by a 4.5 mm summer precipitation event. Recharge volumes were found to be strongly correlated with precipitation magnitude, groundwater mound height, and the duration of the mounding event, and had no significant correlation with antecedent soil moisture. Nitrate leeching was observed beneath the bioretention system, with aquifer nitrate concentrations reaching 3.8 mg/L. While bioretention systems are effective at recharging aquifers in cold climates, groundwater plays an important role in the function of these treatment-infiltration systems and care must be taken to ensure nitrogen contamination does not lead to adverse ecological impacts for wildlife or humans. Future work should look at decreasing the uncertainty in recharges estimates associated with this method and accounting for the impact of heterogeneous and anisotropic aquifers with time-variant infiltration rates and recharge pond geometries at surface.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.Managed Aquifer RechargeMARRechargebioretentionHantushcold climatesGeographyHydrologymaster thesis10.11575/PRISM/39538